Hi All,
Experienced an issue that is pretty troublesome.

Yesterday the day was hot, over 90 degrees and humid in the northeast. The AC compressor wouldn't run, the AC system was not working, and in turn I was sweating.

I tried to diagnose the issue but couldn't figure it out.

• A/C fuses were fine.
• Compressor nose/clutch rotated by hand. Was not stiff, but also was not loose.
• Interior fans were able to engage/disengage, change from recirculation to outside air.
• There was refrigerant in the lines, no leaks.
• Something I did find pretty interesting was that when switching from recirculation to outside air, the recirculated air was actually much warmer than the outside air. Found this out while driving. Put the windows down so that the recirculated air is the same as the outside air, and it was still hotter than putting the system into outside air mode.

Fast forward to today, it is cooler outside (about 75 degrees) and the AC system works. Opened up the hood to see that the AC Compressor clutch was engaged and the system was throwing some pretty cold air.

The question is obviously why did it fail yesterday. If any one has any ideas, or experiences please share. It could be a fail safe, incorrect thermometer readings on the evaporator/condenser coils that prevent corresponding fans to turn on, or something else.

 

That's strange. So yesterday you set it to LO and it still wasn't working?

 

This is the condition you are mentioning. It could, or could not be the problem. Many people have had to do $2000 plus repairs of new compressors because of this less that $20 Sensor. It will keep the Compressor from coming on when it goes bad and it see the incorrect milliamps. Works sometimes, then sometimes not, until goes out for good.

Toyota compressor a/c flow sensor switch

Goggle it.

 

Consumer Reports shows a poor rating for the climate control system on the 2017 GS350. Everything else is excellent for reliability. There must have been a supplier issue for that year.

 

He is saying specifically his Compressor would not run.

 

There is a refrigerant sight glass. It's in front of condenser on top drivers side.

 

Hi All,
Thank you for the replies. I'll see if I can get a scan tool in there to see if there are any codes. I currently do not have a check engine light.

As an update, today a similar thing happened. Got in my car to go to lunch and the AC wouldn't turn on. It was hot outside, however, it started to rain and the temperature dropped. It went from 82 degrees to 75, and the AC Compressor turned on putting out cool air. What I did notice this time is that the driver side vents were blowing cool air, the passenger side was not. Adding that to the list of things I noticed:

• A/C fuses were fine.
• Compressor nose/clutch rotated by hand. Was not stiff, but also was not loose.
• Interior fans were able to engage/disengage, change from recirculation to outside air.
• There was refrigerant in the lines, no leaks.
• Something I did find pretty interesting was that when switching from recirculation to outside air, the recirculated air was actually much warmer than the outside air. Found this out while driving. Put the windows down so that the recirculated air is the same as the outside air, and it was still hotter than putting the system into outside air mode.
• AC works when ambient temperature is below 80.
• When AC is actually on, driver side vents blow cool air, passenger side does not. This happens with dual mode either on or off.

Again, any help is appreciated. Tonight I'll see if I can get an OBD reader in there even though I do not have a CEL. I read somewhere there is an AC diagnostics test that the car can run and return codes, I'll see if this is possible for my model (2013 GS350). If the AC compressor turns on ill take a look at the sight glass. At this point I'm thinking it's an evaporator issue, blower motor issue, or a sensor issue.

 

I recently had AC issues with my '13 GS but it due to a bad O-Ring (https://www.clublexus.com/forums/gs-...l#post11040131). My A/C didn't get colder than 70 degrees (i measured with a thermometer) regardless of the temperature outside, the fan speed, recirculated mode, etc due to the o-ring/leak. There is a servo motor recall on all 4GS vehicles extending from early build 2012/2013 GS's through 2020.

Your symptoms are quite different from mine but I think you're on the right track with a potential temperature sensor issue since the AC works depending on the ambient temperature outside. Hope you narrow it down as the temps are getting up there and having AC issues right now is very inconvenient.

 

Are your radiator fans working? They need to be at full speed when your Compressor is running. (Unless your ambient temp is like 60 or below)

You could rent refrigerant gauges or buy a cheap set to help diagnose.

You could have a leak and still have refrigerant in the system.

You could be low in refrigerant and the gauges read close to normal if the radiator fans aren't running at full speed.

There could also be something blocking the condenser coil keeping air from passing over it and causing the compressor to shut off on high discharge pressure.

 

Quick update, ran the on-board diagnostics (the ignition on the "ON" status, press at same time Recirculation + Auto button) and got code d23 to pop up. If Lexus has not changed the meaning of these codes then this is likely the Pressure Switch Circuit code. This weekend I'll try to diagnose further by checking the sensor and the wiring harness.

But if someone does have an issue or spare time, please do this quick diagnostic check to see if you get any code other than "00" which means everything is all right. Momentarily i actually got the "00" code when things were working fine for a little bit.

 

All,
The issue has been fixed. It ended up being the pressure sensor that was not working correctly. Took it to a local mechanic and told them to swap out the pressure sensor and it fixed the problem.
Refrigerant levels were not changed, and I ended up using a used pressure sensor from a Lexus CT.

 

@revesalex glad to hear you got it working without a trip to the dealer. Just curious: how much was the pressure sensor and cost to replace?

 

Sensor was $98 used, between $170 - $240 new.
Since the mechanic didn't have to "diagnose" the issue they charged me 1/2 labor - $50.

Total was approximately. $150.

 

Clearly chalk that up as a big WIN!

 

Nice! Thanks for following up with us in case we experience that in the future.